Zhang Wei, Ille Sebastian, Schwendner Maximilian, Wiestler Benedikt, Meyer Bernhard, Krieg Sandro M
Departments of1Neurosurgery and.
2Diagnostic and Interventional Neuroradiology, Technical University of Munich School of Medicine, Munich, Germany.
J Neurosurg. 2022 Feb 25;137(4):1114-1123. doi: 10.3171/2021.12.JNS212106. Print 2022 Oct 1.
Preoperative fiber tracking (FT) enables visualization of white matter pathways. However, the intraoperative accuracy of preoperative image registration is reduced due to brain shift. Intraoperative FT is currently considered the standard of anatomical accuracy, while intraoperative imaging can also be used to correct and update preoperative data by intraoperative MRI (ioMRI)-based elastic fusion (IBEF). However, the use of intraoperative tractography is restricted due to the need for additional acquisition of diffusion imaging in addition to scanner limitations, quality factors, and setup time. Since IBEF enables compensation for brain shift and updating of preoperative FT, the aim of this study was to compare intraoperative FT with IBEF of preoperative FT.
Preoperative MRI (pMRI) and ioMRI, both including diffusion tensor imaging (DTI) data, were acquired between February and November 2018. Anatomy-based DTI FT of the corticospinal tract (CST) and the arcuate fascicle (AF) was reconstructed at various fractional anisotropy (FA) values on pMRI and ioMRI, respectively. The intraoperative DTI FT, as a baseline tractography, was fused with original preoperative FT and IBEF-compensated FT, processes referred to as rigid fusion (RF) and elastic fusion (EF), respectively. The spatial overlap index (Dice coefficient [DICE]) and distances of surface points (average surface distance [ASD]) of fused FT before and after IBEF were analyzed and compared in operated and nonoperated hemispheres.
Seventeen patients with supratentorial brain tumors were analyzed. On the operated hemisphere, the overlap index of pre- and intraoperative FT of the CST by DICE significantly increased by 0.09 maximally after IBEF. A significant decrease by 0.5 mm maximally in the fused FT presented by ASD was observed. Similar improvements were found in IBEF-compensated FT, for which AF tractography on the tumor hemispheres increased by 0.03 maximally in DICE and decreased by 1.0 mm in ASD.
Preoperative tractography after IBEF is comparable to intraoperative tractography and can be a reliable alternative to intraoperative FT.
术前纤维束示踪（FT）能够显示白质通路。然而，由于脑移位，术前图像配准的术中准确性会降低。术中FT目前被认为是解剖准确性的标准，而术中成像也可用于通过基于术中磁共振成像（ioMRI）的弹性融合（IBEF）来校正和更新术前数据。然而，由于除了扫描仪限制、质量因素和设置时间外，还需要额外采集扩散成像，术中纤维束示踪的应用受到限制。由于IBEF能够补偿脑移位并更新术前FT，本研究的目的是比较术中FT与术前FT的IBEF。
在2018年2月至11月期间采集术前磁共振成像（pMRI）和ioMRI，两者均包括扩散张量成像（DTI）数据。分别在pMRI和ioMRI上，以不同的分数各向异性（FA）值重建基于解剖的皮质脊髓束（CST）和弓状束（AF）的DTI FT。术中DTI FT作为基线纤维束示踪，分别与原始术前FT和IBEF补偿的FT融合，这两个过程分别称为刚性融合（RF）和弹性融合（EF）。分析并比较了手术侧和非手术侧半球在IBEF前后融合FT的空间重叠指数（骰子系数[DICE]）和表面点距离（平均表面距离[ASD]）。
分析了17例幕上脑肿瘤患者。在手术侧半球，经DICE测量，CST术前和术中FT的重叠指数在IBEF后最大显著增加0.09。观察到融合FT的ASD最大显著减少0.5mm。在IBEF补偿的FT中也发现了类似的改善，肿瘤半球的AF纤维束示踪在DICE中最大增加0.03，在ASD中减少1.0mm。
IBEF后的术前纤维束示踪与术中纤维束示踪相当，可成为术中FT的可靠替代方法。
